<?php
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package	CodeIgniter
 * @author	EllisLab Dev Team
 * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
 * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	http://opensource.org/licenses/MIT	MIT License
 * @link	https://codeigniter.com
 * @since	Version 1.3.0
 * @filesource
 */
defined('BASEPATH') or exit('No direct script access allowed');

/**
 * SQLite Database Adapter Class
 *
 * Note: _DB is an extender class that the app controller
 * creates dynamically based on whether the query builder
 * class is being used or not.
 *
 * @package CodeIgniter
 * @subpackage Drivers
 * @category Database
 * @author EllisLab Dev Team
 * @link https://codeigniter.com/user_guide/database/
 */
class CI_DB_sqlite_driver extends CI_DB
{

    /**
     * Database driver
     *
     * @var string
     */
    public $dbdriver = 'sqlite';
    
    // --------------------------------------------------------------------
    
    /**
     * ORDER BY random keyword
     *
     * @var array
     */
    protected $_random_keyword = array(
        'RANDOM()',
        'RANDOM()'
    );
    
    // --------------------------------------------------------------------
    
    /**
     * Non-persistent database connection
     *
     * @param bool $persistent            
     * @return resource
     */
    public function db_connect($persistent = FALSE)
    {
        $error = NULL;
        $conn_id = ($persistent === TRUE) ? sqlite_popen($this->database, 0666, $error) : sqlite_open($this->database, 0666, $error);
        
        isset($error) && log_message('error', $error);
        
        return $conn_id;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Database version number
     *
     * @return string
     */
    public function version()
    {
        return isset($this->data_cache['version']) ? $this->data_cache['version'] : $this->data_cache['version'] = sqlite_libversion();
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Execute the query
     *
     * @param string $sql
     *            query
     * @return resource
     */
    protected function _execute($sql)
    {
        return $this->is_write_type($sql) ? sqlite_exec($this->conn_id, $sql) : sqlite_query($this->conn_id, $sql);
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Begin Transaction
     *
     * @return bool
     */
    protected function _trans_begin()
    {
        return $this->simple_query('BEGIN TRANSACTION');
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Commit Transaction
     *
     * @return bool
     */
    protected function _trans_commit()
    {
        return $this->simple_query('COMMIT');
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Rollback Transaction
     *
     * @return bool
     */
    protected function _trans_rollback()
    {
        return $this->simple_query('ROLLBACK');
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Platform-dependant string escape
     *
     * @param
     *            string
     * @return string
     */
    protected function _escape_str($str)
    {
        return sqlite_escape_string($str);
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Affected Rows
     *
     * @return int
     */
    public function affected_rows()
    {
        return sqlite_changes($this->conn_id);
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Insert ID
     *
     * @return int
     */
    public function insert_id()
    {
        return sqlite_last_insert_rowid($this->conn_id);
    }
    
    // --------------------------------------------------------------------
    
    /**
     * List table query
     *
     * Generates a platform-specific query string so that the table names can be fetched
     *
     * @param bool $prefix_limit            
     * @return string
     */
    protected function _list_tables($prefix_limit = FALSE)
    {
        $sql = "SELECT name FROM sqlite_master WHERE type='table'";
        
        if ($prefix_limit !== FALSE && $this->dbprefix != '') {
            return $sql . " AND 'name' LIKE '" . $this->escape_like_str($this->dbprefix) . "%' " . sprintf($this->_like_escape_str, $this->_like_escape_chr);
        }
        
        return $sql;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Show column query
     *
     * Generates a platform-specific query string so that the column names can be fetched
     *
     * @param string $table            
     * @return bool
     */
    protected function _list_columns($table = '')
    {
        // Not supported
        return FALSE;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Returns an object with field data
     *
     * @param string $table            
     * @return array
     */
    public function field_data($table)
    {
        if (($query = $this->query('PRAGMA TABLE_INFO(' . $this->protect_identifiers($table, TRUE, NULL, FALSE) . ')')) === FALSE) {
            return FALSE;
        }
        
        $query = $query->result_array();
        if (empty($query)) {
            return FALSE;
        }
        
        $retval = array();
        for ($i = 0, $c = count($query); $i < $c; $i ++) {
            $retval[$i] = new stdClass();
            $retval[$i]->name = $query[$i]['name'];
            $retval[$i]->type = $query[$i]['type'];
            $retval[$i]->max_length = NULL;
            $retval[$i]->default = $query[$i]['dflt_value'];
            $retval[$i]->primary_key = isset($query[$i]['pk']) ? (int) $query[$i]['pk'] : 0;
        }
        
        return $retval;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Error
     *
     * Returns an array containing code and message of the last
     * database error that has occured.
     *
     * @return array
     */
    public function error()
    {
        $error = array(
            'code' => sqlite_last_error($this->conn_id)
        );
        $error['message'] = sqlite_error_string($error['code']);
        return $error;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Replace statement
     *
     * Generates a platform-specific replace string from the supplied data
     *
     * @param string $table            
     * @param array $keys            
     * @param array $values            
     * @return string
     */
    protected function _replace($table, $keys, $values)
    {
        return 'INSERT OR ' . parent::_replace($table, $keys, $values);
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Truncate statement
     *
     * Generates a platform-specific truncate string from the supplied data
     *
     * If the database does not support the TRUNCATE statement,
     * then this function maps to 'DELETE FROM table'
     *
     * @param string $table            
     * @return string
     */
    protected function _truncate($table)
    {
        return 'DELETE FROM ' . $table;
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Close DB Connection
     *
     * @return void
     */
    protected function _close()
    {
        sqlite_close($this->conn_id);
    }
}
